A driver who feels impaired decides to drink strong coffee, take a cold shower and get some fresh air before driving home. What actually happens to their blood alcohol?

Why A is correct

Nothing available at a kitchen table changes the rate at which the liver clears alcohol. Metabolism proceeds at a roughly fixed pace of about one standard drink per hour regardless of coffee, cold water, exercise or willpower, and no amount of stimulation reverses impairment already present in the central nervous system. What caffeine does supply is a wide-awake feeling in a driver whose judgement, divided attention and reaction time remain degraded. That is arguably worse than feeling sleepy, because it removes the last internal signal that might have told the driver to stop.

Why the other options are wrong

B. It stops changing entirely until the driver sleeps

Nothing sharpens this away either. Clearance continues at its own pace whether somebody sleeps, showers or sits perfectly still, so the realistic version of sleeping it off is spending several hours doing nothing while the body goes on clearing alcohol at the rate it was already managing. That is the whole trick, and coffee features in it nowhere at all.

C. It rises briefly and then drops below where it started

Nothing about cold or exercise pushes blood alcohol upward once absorption has settled. The pattern the body follows is a slow decline, not a late spike.

D. It falls faster, because caffeine and cold accelerate metabolism

Caffeine alters alertness, not clearance. Confusing the two is what puts a wide-awake but still-impaired driver behind the wheel, genuinely convinced the coffee achieved something.

On the road

Two drinks at eleven, keys in hand at one. The body has metabolised roughly two standard drinks' worth, the pulse is racing from the coffee, and driving is still the wrong call. Time was the only variable that mattered, and not enough of it passed.

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